A variety of image devices, such as scanners, digital cameras, digital video cameras and a variety of display panels are popularized more and more with the popularity of the Internet and the enhancement of computer hardware.
Most display systems have a nonlinear display property, known as the gamma effect, which makes the brightness provided by a display system absolutely and directly proportioned to an output voltage. Because of this gamma effect, an image signal is usually corrected with a gamma curve before being displayed. Therefore, the nonlinear property of the display system can reversely be compensated in order to obtain a more real and colorful images display.
However, when the modern gamma correction is performed on the detailed image contents (i.e. high-frequency signals), such as the edge of a region or the lines of words, broken lines or color washout may easily occur on the words.